In a paper doubtless to be horribly misconstrued by much of the media (sample headline: Facebook linked to big brains), a new research paper has found a link between the size of your Facebook friend network, and the density of certain areas of the brain.

What researchers have found is that a larger number of friends can be statistically linked to greater grey matter density in the right superior temporal sulcus, left middle temporal gyrus and entorhinal cortex. These are areas of the brain associated with social perception and associative memory. They also found that the size of the amygdala correlated to size of both online and offline friendship networks.

What's important to note here is that there's no attempt by the researchers to set up a causation link between the two. Facebook does not make your brain bigger. In fact, what's far more likely is that people with this area of their brain enlarged are naturally more social and able to form friend networks— some for the meatspace, some for the digital, and some for both.

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Those three parts of the brain specifically linked to a large group of Facebook friends are generally thought to do the following:

The superior temporal sulcus plays a role in our ability to perceive a moving object as biological, and structural defects in this region have been identified in some children with autism. The entorhinal cortex, meanwhile, has been linked to memory and navigation – including navigating through online social networks. Finally, the middle temporal gyrus has been shown to activate in response to the gaze of others and so is implicated in perception of social cues.

This research is intriguing because it raises questions about how digital social networks — be they forums, Facebook, or Observation Deck — are linked to the physiology of the brain.